Thursday, June 9, 2022

How to get started with GCP ?

Anyone can start building on Google Cloud with $300 in free credits for 90 days and free usage of 

20+ products like Compute Engine and Cloud Storage, up to monthly limits.

Visit:    for details

Signup form is here to use $300 

Cloud Security

 Why Cloud Security ??

Cloud security, also known as cloud computing security, is a collection of security measures designed to protect cloud-based infrastructure, applications, and data. These measures ensure user and device authentication, data and resource access control, and data privacy protection. They also support regulatory data compliance. Cloud security is employed in cloud environments to protect a company's data from distributed denial of service (DDoS) attacks, malware, hackers, and unauthorized user access or use.

Cloud security is critical since most organizations are already using cloud computing in one form or another. This high rate of adoption of public cloud services is reflected in Gartner’s recent prediction that the worldwide market for public cloud services will grow by 23.1% in 2021.

Security in cloud computing is crucial to any company looking to keep its applications and data protected from bad actors.

Wednesday, October 27, 2021

Proxmox USB device at VM


Login to console of mail Proxmox hypervisor

run the command: lsusb and collect USB device ID

root@proxmox:~# lsusb

if we wants to attach this usb  (usb-device-id 8564:7000) to vm id 145 

first stop VM 145 and run below command

root@proxmox:~# qm set 145 -usb0 host=8564:7000

Now start VM ID-145 and check the device with lsblk

# lsblk or fdisk -l 
to find acutal device with partition and finally mount with mount command # mount /dev/sdx1 /mnt

Sunday, October 24, 2021

Iredmail password change md5 ssha512

 To generate a password hash for a new password, please use doveadm command.

Generate a SSHA512 password hash:

$ doveadm pw -s 'ssha512' -p '123456'


Generate a BCRYPT password hash on BSD system:

$ doveadm pw -s 'blf-crypt' -p '123'


SQL backends

To reset password for user, please login to SQL server as either SQL root user or vmailadmin user (note: sql user vmail has read-only privilege to vmail database, so you cannot use it to change user password), then execute SQL commands to reset password:

sql> USE vmail;

sql> UPDATE mailbox SET password = '{SSHA512}$1$KxfQLbMV$Pq3x21nQEYMm6eFUrVJOS.' WHERE username = '';

Saturday, October 23, 2021

Fail2Ban jail search and unban


** To see / get the actual jail names

#fail2ban-client status | grep "Jail list" | sed -E 's/^[^:]+:[ \t]+//' | sed 's/,//g' 

example output:: ssh-iredmail roundcube-iredmail postfix-iredmail dovecot-iredmail pam-generic ssh-iptables

** To Unban IP use bellow command

#fail2ban-client set JAIL_NAME unbanip

fail2ban-client set ssh-iredmail unbanip

fail2ban-client set roundcube-iredmail unbanip

fail2ban-client set postfix-iredmail unbanip

fail2ban-client set dovecot-iredmail unbanip

fail2ban-client set ssh-iptables unbanip

fail2ban-client set pam-generic unbanip

Clear Memory / RAM cache in Linux


How to Clear Cache in Linux?

Every Linux System has three options to clear cache without interrupting any processes or services.

1. Clear PageCache only.

# sync; echo 1 > /proc/sys/vm/drop_caches

2. Clear dentries and inodes.

# sync; echo 2 > /proc/sys/vm/drop_caches

3. Clear pagecache, dentries, and inodes.

# sync; echo 3 > /proc/sys/vm/drop_caches 

Wednesday, October 20, 2021

Format your Pen drive / USB Flash Drive from Command Prompt

How to  

Step 1: Type cmd in the search box, then you can get the best match called Command Prompt. Right-click on it and choose "Run as administrator".

Step 2: On the Command Prompt window, type diskpart and press "Enter".

type diskpart to format usb flash drive using cmd

Step 3: Type list disk and press "Enter". According to the list disk information, check which disk is your USB flash drive. For example, disk 2.

type list disk to format usb flash drive using cmd

Step 4: Now type select disk 2 and press "Enter".

type select disk 2 to format usb flash drive using cmd

Step 5: Type clean. Wait some time for disk erasing.

type clean to format usb flash drive using cmd

Step 6: Type create partition primary and press "Enter".

type create partition primary to format usb flash drive using cmd

Step 7: After diskpart successfully created the specified partition, type format fs=ntfs and press "Enter". If you prefer other file system formats, change the command ntfs to the desired one such as fat32, exfat, etc.

type format fs=ntfs to format usb flash drive using cmd

Step 8: Type assign to create a drive letter to the flash drive.

type assign to format usb flash drive using cmd

Outlook Sync send / recieve issue


Please follow the attached steps to overcome the slow sync issue from Laptop/Desktop.